A scoping study on measuring and monitoring tools and technology for precision irrigation

This scoping study is designed to advance high standards of precision in management of water and develop efficient methods of irrigation prescription to reduce losses and improve water use efficiency. All aspects of irrigation process are considered in this study to include various components of farm water storage and distribution systems to facilitate accurate accounting of water. In this study, we will attempt to: * Identify key attributes and specifications for various tools (sensors and control systems) for precision irrigation management; * Develop strategies to fill current gaps in the functionality of various tools and technology available for irrigation and * Prioritise opportunities to refine and/or develop new tools and technology to increase on-farm precision and meet off-farm hydrology needs

Selecting an appropriate size for domestic rainwater tanks in Colombo

Both India and Sri Lanka have experienced rapid population growth and migration to the major cities in the past decade. This rapid urbanisation has resulted in overstressing of existing water supply systems, with a loss of recharge areas and an increased depletion of groundwater. These effects have further aggravated the urban water crisis. During the monsoons, the existing drainage systems are overloaded and overflow thereby resulting in flooding causing severe damage to property. Sewage overflows often lead to the outbreak of epidemics and occasionally to the loss of life. Rainwater harvesting systems serve the dual purpose of water storage to reduce urban runoff peak flows as well as augmentation of the existing water supply systems. To achieve minimum costs while optimising the security of supply, rainwater tanks need to be sized taking the local rainfall conditions into consideration. This paper presents a methodology to determine the optimal size of rooftop storage based on historical rainfall data. Annual savings of in-house demand as well as the security of rainwater supply are discussed. The methodology is applied to Colombo in Sri Lanka. A case study is based on 150lpd household demand with 25m2 of roof area in Colombo. The appropriate rainwater tank is determined to be 2000 L in capacity. The resulting water saving is 54% of annual in-house demand and more importantly, zero supply from the tank happens during only one third of the year

Water Sensitive Urban Design: An Investigation of Current Systems, Implementation Drivers, Community Perceptions and Potential to Supplement Urban Water Services

Special Issue: Urban Drainage and Urban Stormwater Managemen

Sizing of Domestic Rainwater Harvesting Systems Using Economic Performance Indicators to Support Water Supply Systems

This paper presents a monitoring-based investigation of rainwater collection systems using economic performance indicators in a group of households with nonconventional end-uses for rainwater that are not traditionally associated with rainwater supply. The monitored data for five household rainwater tank systems were analysed in two stages. For the first stage, the data was empirically analysed to develop a method to predict effective roof catchment areas. For the second stage, the effective roof catchment areas, together with roof area connection percentages, were analysed against different types of water demands in individual households. The individual systems were investigated for yield capacities, costs and water security using a modified Roof Runoff Harvesting Systems average annual yield model based on daily water balance procedures. The Life Cycle Costing analysis of the systems using the model was based on the Capital Recovery Method by taking into consideration the capital costs as well as ongoing costs for maintenance, replacement and operation of the systems. The analysis established the optimal sizing requirements for the studied rainwater tanks and their corresponding roof area connectivity

Experience in the application of permeable interlocking concrete paving in Australia

This paper reports assessments of a range of permeable interlocking concrete pavements (PICP) that have been in service around Australia for periods of around 10 years. Each of the assessments is supported by a critical review of the properties and in-service performance of the pavements based on in-situ measurements and inspections, supplemented by laboratory test data. Factors studied in-clude the infiltration rate, structural properties and performance together with lifespan and physical filtration efficiency. The effects of sediment load and pavement clogging have also been examined. Most of the pavements studied had not been subject to routine or systematic maintenance. Despite this, the study showed that, up to 10 years of service, most pavements were still capable of good in-filtration. Sweeping the pavement surface was shown to be beneficial to infiltration and laboratory tests confirmed that most fine sediment was trapped in the upper portions of the jointing materials. Overall, the results tend to indicate that, at least under Australian conditions, the need to routinely sweep permeable paving may not be as necessary as is often assumed in the Northern Hemisphere.

Stormwater Runoff Modelling in an Urban Catchment to Plan Risk Management for Contaminant Spills for Stormwater Harvesting

Water quality is a key consideration for urban stormwater harvesting via aquifers. This study assessed catchment spill management options based on a calibrated dynamic wave routing model of stormwater flow in an urban catchment. The study used measured travel times, pluviometer and gauging station observations from 21 storms to calibrate a stormwater model to simulate transport of pollutants from spill locations to the point of harvest. The simulations considered the impact of spill locations, spill durations, storm intensities and storm durations on the pollutant concentration at the point of harvest and travel time of a pollutant spill to the harvesting point. During dry weather, spill events travelled slower than spills occurring during wet weather. For wet weather spills, the shortest travel times tended to occur in higher intensity storms with shorter duration, particularly when a spill occurred in the middle of the storm. Increasing the intensity of rainfall reduced the peak concentration of pollutant at the harvest point via dilution, but it also reduced the time of travel. On a practical level, due to the short response times in urban catchments, management of spills should be supported by automated detection/diversion systems to protect stormwater harvesting schemes

Community Acceptance of Water Sensitive Urban Design: Six Case Studies

Executive summary The Socio-Technical Analysis and Community Engagement Research is Task2 of the Goyder Institute funded project, Water Sensitive Urban Design Impediments and Potential Contributions to the SA Urban Water Blueprint. The broader project aims to gain insight into the impediments to mainstream adoption of Water Sensitive Urban Design (WSUD) systems in the Greater Adelaide region. The need for WSUD is becoming paramount as the population of Adelaide continues to grow, placing pressure on existing infrastructure, receiving water bodies and water resources. This project aimed to determine the factors that facilitate or inhibit community acceptance of WSUD. More specifically, it provides an understanding of: • Perceived benefits of WSUD by community members • Perceived barriers affecting the uptake of WSUD by the community • Community responses to WSUD • Ways to improve community acceptance of WSUD over the long term The research design adopted a case study approach because of its ability to integrate multiple sources of information within a single site and also to contact community directly living in developments designed with WSUD approaches. The six case studies were Christy Walk, Lochiel Park, Mawson Lakes, Springbank Waters, Mile End streetscape and Harbrow Grove Reserve. They provided opportunity for comparison of findings across a diverse range of WSUD installations and represented WSUD operating at different scales and in both new developments and retrofitting existing suburban areas. Consistent with a case study approach, for each site there were three main components to the data collection: 1) analysis of the technical aspects of the WSUD sites, 2) interview material from key informants, focus groups and short interviews, 3) questionnaires to assess attitudes to the environment and water. Findings Overall there was strong support for WSUD innovations. There were two categories of WSUD features:- • WSUD features that had instant appeal included features that improved aesthetics, greenscape, recreational amenity, and increased resident control over their own water supply • WSUD features that were less obvious but gained community support once the features were explained and understood. They included features that improved the quality of water runoff or flood mitigation. There were no specific WSUD features that were disliked by respondents rather there were problems that could arise with any feature and, if left unaddressed, could jeopardise acceptance of WSUD both long-term and to the wider community. The barriers, which could be cumulative, included: 1. Poor functioning of the WSUD systems, often occurring soon after installation: Poorly functioning WSUD features make developers, residents, and councils reluctant to invest in them. Increased availability of technical knowledge, and training of contractors and those who oversee the work seems to be required if WSUD is not to get a reputation of being “too difficult”. 2. Inadequate maintenance and ongoing management: Respondents wanted a long-term maintenance plan including a plan for the hand-over to council so councils and residents are aware of the long-term maintenance requirements and costs. 3. Lack of community consultation: Most obviously communities cannot support WSUD facilities if they do not know that they exist. Understanding a WSUD facility is likely to need two-way communication such as discussion groups and tours of the facility rather than one way communication such as the distribution of flyers. Two-way dialogue also has the added benefit of directly hearing back from the community aspects about the WSUD feature that they particularly like or dislike. This type of feedback can assist future innovation and development of WSUD. 4. Uncertainties about costs: All residents in the new sites had paid extra for their home with WSUD and other features; however poor design, functioning and maintenance, ..